1. Field of the Invention
The present invention relates to an image forming apparatus in which billing is calculated according to execution of a print operation.
2. Description of the Related Art
In the related art, there is known an image forming apparatus in which a dedicated mechanical hard counter used for calculation of billing is provided, counting is performed for each of output sheets and the billing is performed.
The billing is performed based on a difference in, as objects of the billing, the number of sheets on which printing is performed, the size, the material (for example, normal paper or OHP sheet) and the like. For example, in the case where the unit cost of a sheet of an A4 size is set to 10 yen, when the number of sheets printed is 10, the total of 100 yen of “unit cost×the number of sheets” is billed.
Besides, as another billing method, there is an image forming apparatus in which the usable number of sheets is previously stored by storage means and is set, a print operation is permitted within the set number of sheets, and the print operation becomes unable to be performed at the time point when the number of sheets printed exceeds the set number of sheets (for example, JP-A-2003-122209).
In the image forming apparatus having the billing management function as stated above, a definite numerical value of, for example, a unit cost, a multiplying rate or an adding rate, which is to become a standard for billing is generally called a “billing rate”.
On the other hand, in recent years, also in a copying machine as an image forming apparatus, a stand-alone machine tends to reduce, and a machine which is connected to a network and has multi-functions of a copier, a printer, a facsimile and the like is becoming mainstream. In accordance with this, the kinds of objects which are counted for billing are increased. Then, instead of a hard counter, a so-called soft counter using an SRAM mounted with a backup battery or a nonvolatile memory such as a writable EEPROM comes to be used as a billing counter (for example, JP-A-2004-325490).
In the case of a soft counter, a space is not required as compared with a mechanical counter, and it is sufficient if there is a space in which a RAM and a ROM can be mounted on a board. Further, although depending on the capacity of a memory, a certain degree of many counters can be provided.
On the other hand, colonization on the market quickly spreads, and it appears that it becomes necessary to include more counters in order to meet the needs of users.
As compared with the mechanical counter, in the soft counter, the kinds of manageable counters are remarkably increased. However, a further improvement is desired from the demands of users.
Although the soft counter is used, in the present circumstances, the counter is classified merely by a print mode or a sheet size. Specifically, the classification is performed merely based on whether the color mode is full color, mono color or white and black, whether the print side is a single side or double sides, whether the sheet size is a large size or a small size, whether the function is copy, print or fax, or the kind of the combination of these.